Fuels nowadays consist not of a single chemical compound, but of a plurality of so-called fractions of differing composition and concentration. Each of the fractions has differing chemical and physical properties axed accordingly provides different properties as a motor fuel component.
The strategy and tuning of current combustion engines are directed to achieving, from the overall mixture of properties present in the fuel, optimum motor operation and combustion, particularly with regard to a reduction in environmental damage.
The highly volatile components, particularly alcohols, in the fuel tank lead to evaporation emissions, which can be captured in a storage device on a filter used with the engine. Since, in particular, the highly volatile components evaporate, they have a composition which is different from the mixture contained in the fuel tank.
Storage devices are known for reducing evaporation emissions from vehicles with internal combustion engines. One component of such systems is a control device to empty the storage device by connecting it to the conbustion process.
Accordingly, an object of collecting the fuel components which can be denoted "evaporation emissions" is the prevention of their release into the atmosphere.
The object of the controlled feed of the initially collected together portions is to empty or regenerate what is collected in the storage device in order that the device is then available for a fresh filling process.
The construction and mode of operation of such systems is known to be matched to the intended purpose and, in particular, these are known to consist of:
A storage device, preferably an active charcoal device, is charged with fuel components essentially by the vapor pressure of the fuel. Regeneration takes place as a rule by means of the inlet suction of the engine, preferably under operating conditions. The admixture of the contents of the storage device to the remainder of the combustion mix (fuel) should cause as little disturbance as possible to the fuel and the operation of the engine. PA0 matched storage device volume, number of storage devices and their composition; PA0 heating of the storage device to render the light vaporizing components ready for use even with unfavorable operating conditions (e.g., low temperatures) or for an active solution to the process of selection of fuel components; PA0 active additional measuring units (e.g., pumps and metering valves); PA0 means to determine the quantity and concentration of the contents of the storage devices; PA0 heating devices for the fuel container in order to provide support for carrying out an active thermal selection process to move volatile fractions from the fuel mix into one or more storage devices. PA0 the selection of the individual components is made on a basis of the ability to differentiate their vaporization temperatures and vaporizing behavior. PA0 the temperature for allocating the fraction is generated as a result of natural thermal processes (temperature reduction and rise from uncontrolled external influences such as tank filling, change in ambient temperature, etc.). PA0 the temperature for allocating the fraction is generated by actively heating at least parts of the fuel. PA0 the collection of the fractions takes place in a storage device. PA0 the collection of the fractions takes place in several switchable storage devices, each storage device being selected corresponding to different vaporizing temperature ranges for the fuel components to be stored in the respective storage device. PA0 the selection of the fractions takes place on the basis of the differing absorption behavior of parallel storage devices. PA0 the storage device(s) is/are active charcoal containers.